German Patent Application Publication DE 10 2007 005 665 A1 discloses a communication system for wirelessly transferring data via radio links. In this known communication system a communication network is built-up as a multi hop network starting from a root node. The communication between the individual nodes is according to the Bluetooth standard. The root node is a dedicated participant of the communication network which connects to spatially adjacent participants, which in turn connect to further spatially adjacent participants, wherein they form further nodes of the network themselves. Thus, the communication network builds-up in a tree structure, which, however, does not need to be regular, i.e. the logical arrangement of the nodes may differ from the functional command structure of its participants, and may even vary between different times at which the communication network is built-up, for example, due to variable interference of individual radio links.
German Patent Application Publication DE 10 2007 005 665 A1 does not deal with how, in building the communication network, it is acknowledged whether a device which is in the direct reach of the root node or within its indirect reach via other nodes is a desired participant of the communication network to be built-up. In the practical implementation of this known communication system, however, a switch is provided in the respective radio interface which can be set to different values for defining the participants of the respective communication network. Only such devices are incorporated in the communication network built-up starting from the root node, which have been pre-defined in that the switch in their radio interface has been set to the same value as in the root node.
With increasing density of installed photovoltaic power plants the risk increases that neighboring photovoltaic power plants comprise overlapping ranges in wireless communication. With an accidentally same setting of the switches for the network definition in the radio interfaces of the respective participants, an undesired connection between neighboring communication networks may occur. With an even further increasing density the limited number of possible switch positions for network definition in the radio interfaces will even then not be sufficient, when photovoltaic power plants that overlap each other with regard to the range in wireless communication are purposefully set to different network definition values.
US Patent Application Publication 2006/0002328 A1 discloses a network system comprising a plurality of network nodes, each of the network nodes comprising means for temporarily forming a group with at least one of the plurality of network nodes, sending means for sending information which may include voice, text message, images etc. to the group, and receiving means for receiving information from the group. The sending means and the receiving means are configured to provide a direct contact via a radio connection between at least two network nodes of the group.
German Patent Application Publication DE 10 2008 014 574 A1 discloses a solar module comprising an integrated programmable short-range radio controller, for example according to the ZigBee or Bluetooth standard. Sensors which are provided for monitoring operation data of the solar module are connected to the interfaces of the radio controller. In this way, the obtained data are available via radio transmission. One or more central devices receive the data transmitted by the radio controller and store them in a data base. Here, the data are available for further use. The central device may be connected to the internet or a LAN via a gateway.
US Patent Application Publication 2003/0226013 A1 discloses a scalable distributed management of wireless virtual private networks including application of intrusion tolerant concepts to a software infrastructure for supporting secure group applications. This application is suited for use with network layer protocol such as TBRPF and is particularly adapted for wireless networks, most specifically mobile ad hoc networks.
US Patent Application Publication 2005/0055417 A1 discloses a distributed sensor network in which one or more devices forming a collaborative group are associated with a physical phenomenon based on geographical proximity. The sensor network is capable of detecting new phenomena in changing the membership of the collaborative group as the phenomenon changes. Sensors not associated with the detected phenomenon are available to detect new phenomena, and one group may exist per phenomenon. Upon detection of a phenomenon, a group of nodes is formed and a leader node is elected. As the phenomenon changes over time, new devices come into proximity of the phenomenon and are prevented from forming independent groups associated with the phenomenon. This is accomplished in a decentralized way with communication restricted to local neighbors. In a tracking sensor network using a relatively small number of sensors, the sensors are active and maintain a coherent belief associating their measurements with a single common vehicle.
Thus, there still is a need for a method and a radio interface which ensure that a wireless communication network is always only built-up over a fixed group of participants, without increasing the efforts in installing a new photovoltaic power plant or in adding a new component to an existing photovoltaic power plant, for example.